Generally hundreds and thousands of street lamps are installed in such a manner that they can be controlled by a central control processor. However, if the state of operation of a street lamp is to be checked, the actual site of the street lamp has to be visited to confirm the operative state of the street lamp, with the result that too much of the time is consumed.
Further, if a large number of street lamps are to be repaired, large quantities of lamps and ballast coils have to be loaded and carried by a vehicle, and therefore, the repairing team contributes to traffic congestion. At present there are disorder display devices installed at the lower portions of electric poles, but their functions are restricted to displaying power source disorders, ballast coil disorders, lamp disorders and the like. A detailed description of this matter is found in Korean Utility Model Publication No. 89-3957.